The term déjà
vu refers informally to the “as if” experience—as if it’s
happened before, yet it hasn’t. It is also possibly the most commonly
used French term in the English language and is a fertile source for
neologisms, and, indeed, in my Telicom article on neologisms (XXII-2,
2009)2, I alluded to the déjà vu phenomenon as a remarkable
area for new terms. Déjà vu:

• derives from a foreign
language (French),

• involves more neologisms
than in any other study discipline, and

• has been a major source
of personal interest and research for me, to the extent that I am curator
and author of déjà Vu on Scholarpedia.org.

However, I did not discuss
the fascinating new terms relating to the various kinds of déjà

experience in the above
article3. To fill that void, I give a perspective below.

First, the lighter side of
déjà vu4—what it isn’t:

Déjà
boo: The feeling that I’ve been frightened like this before

Déjà
coup: The feeling my government has been overthrown like this before.

Déjà
do: The feeling my hairdresser has given me this cut before.

Déjà
eau: The feeling I’ve smelled this perfume before.

These terms are unacceptable
neologisms because they serve only one purpose—humor. They are neither
parsimonious nor educational. Like all neologisms, new déjà
vu terms must be valuable for their significant empirical or theoretical
scientific phenomenological contributions. The older déjà
experiences5
(a neologism itself) traditionally derive from French terms: We have
continued this application even in English phrases.6

The French term, déjà
vu, is the most familiar déjà experience. It was originally longer:
‘le sentiment du déjà vu’
(Boirac, 1876)7, and ‘sensation du déjà
vu’ (Arnaud, 1896). Meanwhile, tongue-tying alternatives conveying
relatively equivalent meanings—the fausse reconnaissance
or fausse mémoire of Bernard-Leroy, Biervliet (1894), Freud,
Heymans and Laurent; or the souvenir du présent
of Bergson; or the reconnaissance
des phénomènes nouveaux of Bourdon; or the falsa intuizione
di ricordo of Montesano, and the German Erinnerungsfälschunges
(Kraepelin) or fälschen Wiedererkennens
(Lehmann and Linwurzky)—were largely consigned to the dusty archives
of forgotten history. Déjà
Vu—(literally “already seen”) is the generic déjà
experience. My definition is now universally used: “any subjectively
inappropriate impression of familiarity of the present experience with
an undefined past.” 8

Are the different forms of
déjà vu so different that we needed to coin new terms for what
I was generically calling déjà
experiences? Two key pretenders to déjà
vu itself are: déjà éprouvé—already experienced, felt,
attempted, or tried: This fails as a broad generic term because “experienced”
here is in the sense of attempted or tried9
and déjà vécu— implies already lived through, fully experienced
or recollected, intense experiential term, but fails because ‘experienced’
here is the sense of fully experienced, recollected, or lived through,
which would exclude much déjà vu.

By the time of my research
in the late 1970s, there were already 9 other lesser known déjà
terms all decades old, though some such as déjà
voulu were purely theoretical, as true examples were unavailable:

déjà
fait already done

déjà
entendu already heard

déjà
fait already done

déjà
pensé already thought

déjà
raconté already told

déjà
senti already felt emotionally, smelt

déjà
su already known (intellectually)

déjà
trouvé already found (met)

déjà
voulu already wanted

In this context, I wrote (1981):
“At times the demarcation is artificial, as the déjà
experience can coexist in more than one of the above categories. Moreover, the literature and my experience indicate that there are
several other common kinds of déjà
experience that have not yet been categorized”10
For legitimate research, we needed a more adequate vocabulary of subtypes
of déjà vu.

I suggested ten new terms:11

déjà
arrivé already happened

déjà
connu already known (personal knowing)

déjà
dit already said/spoken (content of speech)

déjà
goûté already tasted

déjà
lu already read

déjà
parlé already spoken (act of speech)

déjà
pressenti already ‘sensed’ (as in ‘knew’ it would happen)

déjà
rencontré already met

déjà
rêvé already dreamt

déjà
visité already visited (a locality)

By a felicitous coincidence,
déjà visité and déjà rêvé
were independently developed in theses by Dr Art Funkhouser in Switzerland
and I in 1981.12 In 2006, I began the long, arduous
process of updating my original 1983 book on déjà vu (“The Psychology
of Déjà Vu” to “Déjà
Vu Revisited”), updating the literature (“Déjà
vu: A Second Look”) and creating a glossary and bibliography
(“Déjà vu: Glossary and

Library”)13
This process has been fruitful in many ways for my continual rethinking
of the topic. I realized we needed six more kinds of déjà experience.—the
following borne from necessity:

The thirtieth déjà variant
is being announced for the first time now: déjà préconnaître—already
precognized; psychics who feel they have had the same future impression
before although realistically knowing this was incorrect. Déjà
vu research involves screening for all kinds of déjà
experiences using questions pertaining to these different déjà subtypes
and then amplifying. These terms, therefore, have become part of the
most comprehensive questionnaire on the topic.15
Otherwise we may remain unaware of their presence particularly in patients
with psychosis (originally schizophrenia) (Psychotic Déjà
Vu), temporal lobe disease (Temporal Lobe Déjà Vu), in subjective
paranormal experients (Subjective Paranormal Experience Déjà Vu),
and in ostensible normals (Associative Déjà Vu— the common garden
subtype in ordinary individuals.) These, for historical completeness,
are the 4 legitimate, neologisms reflecting the different nosological
categories of déjà experience I described. They occur with specific
features, in different subpopulations, and are nosologically distinct,
implying possible different causalities for each.16 Neologisms
have relevance and meaning. The different subtypes of déjà experience
incorporate all these different new terms allowing for further research
in this fascinating area.

Mineart, S, Bell, B. Déjà.
What?, Déjà vu rhymes by Stacy Mineart and Bridget Bell. http://www.commonplacebook.com/humor/lists/dejavu.shtm, 2005. Described in Neppe, VM. Does
the definition of déjà vu withstand a quarter of a century
of research? In Neppe VM (Ed): Déjà
Vu: A Second Look. Brainvoyage.com, Seattle. 2006, Chapter 15, 142-163.

Vernon Neppe 1981 (endnote
#8). This generic hybrid is itself a neologism; it covers all the 30
different kinds listed.

19 new deja experiences and
four new déjà vu nosological subtypes have been described by
Prof. Vernon Neppe. 2 of these terms, déjà
rêvé and déjà visité were independently described in
the same year by Dr Art Funkhouser. With the 11 previous déjà
experiences including déjà vu itself, these form the base for
our vocabulary today.

Professor Emile Boirac was
rector of the Dijon Academy in France and a famous psychic investigator,
who published a letter using the term in the Révue Philosophiqu

Although this is the usual
cited source, the earliest is my 4 volume Doctoral Thesis Neppe VM.
A study of Déjà vu experience. PhD Med thesis. Johannesburg, University
of the Witwatersrand. 1981; 1-1-588, Vol 1-4.

These two terms
are discussed in more detail in my book Neppe VM (Ed): Déjà
Vu: A Second Look. Brainvoyage.com, Seattle. 2006.

(the paradox of exact differentness
or different sameness.)
We know this use of an adjective moves away from the traditional use
of past participle verbs (e.g.
the ‘vu’ of deja vu is the past participle form of the verb voir,
‘to see’), but this appears the best option and at any rate is not
so far off the mark, as the past participle forms of verbs are also
sometimes used as adjectives.